Ablation catheter system with safety features

ABSTRACT

A medical system for delivering treatment or therapy to a patient has a kill switch for interrupting the delivery. The kill switch, which can disrupt the delivery directly or can cause an error message to be generated that disrupts the delivery, can be activated by the operator or remotely. In an ablation catheter system, a kill switch mechanism immediately and abruptly terminates delivery of ablation treatment or therapy.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional of, commonly assigned U.S.patent application Ser. No. 13/838,534, filed Mar. 15, 2013, which inturn is a continuation-in-part of, commonly assigned, U.S. patentapplication Ser. No. 13/415,454, filed Mar. 8, 2012, now U.S. Pat. No.9,289,258, which in turn is based upon and claims the benefit of thepriority of the filing date of commonly assigned U.S. Provisional PatentApplication Ser. No. 61/450,236, filed Mar. 8, 2011, each of whichapplications is incorporated herein in its entirety.

FIELD OF INVENTION

The present invention relates generally to systems, catheters, andmethods for performing targeted tissue ablation in a subject. Moreparticularly, the present invention provides an ablation system having aquick cut-off mechanism, also known as a “kill switch”.

BACKGROUND OF THE INVENTION

Tissue ablation is used in numerous medical procedures to treat apatient. Ablation can be performed to remove undesired tissue such ascancer cells. Ablation procedures may also involve the modification oftissue without removal, such as to interfere with or stop electricalpropagation through cardiac tissue in a patient with an arrhythmia.Often the ablation is performed by passing energy, such as electricalenergy, through one or more electrodes to cause the tissue in contactwith the electrodes to heat up to an ablative temperature. Otherelectrical energies such as laser, microwave, ultrasound, etc., caneffect change in tissue. Alternatively, non-electrical therapies such asmedications, stem cells, biologics, or cryotherapy can be used to alterthe structure and function of tissue.

Atrial fibrillation refers to a type of cardiac arrhythmia where thereis disorganized electrical conduction in the atria causing rapiduncoordinated contractions that result in ineffective pumping of bloodinto the ventricle and a lack of synchrony. During atrial fibrillation,the atrioventricular node receives electrical impulses from numerouslocations throughout the atria (such as the pulmonary veins) instead ofonly from the sinus node. This condition overwhelms the atrioventricularnode, resulting in an irregular and rapid heartbeat. As a result, bloodpools in the atria and increases the risk of blood clot formation.

Atrial fibrillation treatment options are limited. Three knowntreatments, lifestyle change, medical therapy and electricalcardioversion, all have significant limitations. Electricalcardioversion attempts to restore sinus rhythm but has a high recurrencerate. In addition, if there is a blood clot in the atria, cardioversionmay cause the clot to leave the heart and travel to the brain or to someother part of the body, which may lead to a stroke.

Various ablation techniques have been proposed to treat atrialfibrillation, including the Cox-Maze procedure, linear ablation ofvarious regions in the atrium, and circumferential ablation of pulmonaryvein ostia. Other linear lesions can target the roof of the left atrium,the mitral valve isthmus, superior vena cava, and the ligament ofMarshall.

Certain types of arrhythmias have critical components that requireablation near the normal conduction system of the heart (AV junctionand/or His bundle). These arrhythmias typically include paraseptalbypass tracts, AV node reentrant tachycardia, and certain atrial andventricular tachycardias. Inadvertent ablation misapplications intreating such problems may result in complete heart block and requireimplantation of a permanent pacemaker, a known possible complication ofthe procedure. In addition, other untoward events may occur duringablative procedures in which the body may exhibit early signs (such as achange in heart rate, oxygen saturation, and/or blood pressure), whichmay indicate perforation. When this occurs, the device or cathetercreates a hole in the heart wall leading to fluid accumulation in thepericardial sac and a life-threatening condition called cardiactamponade. Blood needs to be rapidly removed from the pericardial sac bya needle or surgical window along with any supportive measures (bloodand/or fluids) as well as possible surgical repair. Each and everyuntoward event has the potential for medical legal action in which anydelay in terminating therapy may be highly scrutinized.

In applying ablation techniques to treat arryhthmias, the distal tip ofan ablation catheter is advanced to a desired location in a patient'sheart. Radiofrequency or laser energy, for example, is transmitted tothe distal tip of a catheter from a point adjacent and/or external to acatherization laboratory upon signal from the doctor or operator to atechnician or nurse who operates a generator (such as an RF generator)or a laser, to deliver ablation therapy or energy. Whenever the doctoror operator wants the ablation therapy or energy to be discontinued, thedoctor or operator signals the technician or nurse, usually by voicecommand (“Stop!!!” or “Off!”). However, there is an inherent delay inthis procedure, which could result in damage to a patient, such as heartblock, perforation, or phrenic nerve paralysis, if the ablation energyis not terminated quickly enough. In addition, it is not very practicalfor the sterile catheter operator to have direct and immediate controlover any switching mechanism contained on the non-sterile generator orconsole to terminate therapy as they are concurrently configured. Also,these ablation generators and consoles are typically not easilyaccessible to the operator and, if placed in such a location, wouldpotentially be disruptive to lab staff and operations. Alternativelythere could be foot control for the doctor or operator to terminate theablation energy, but using a foot control may be awkward and difficultto control (especially because two foot pedals would potentially be usedin concert: one for fluoroscopy and the other for an on/off switch). Inaddition, accidentally stepping on the on/off foot pedal switch as itcurrently functions can potentially turn on therapy and causeinadvertent ablative therapy delivery with unintended injury to theheart, its conduction, and other structures.

Medical devices having on/off or cut-off mechanisms are known. See, forexample, U.S. Pat. Nos. 5,951,461, 6,165,206, 6,235,022, 6,808,499,7,717,932, and 7,763,033 and U.S. Published Patent Applications Nos.2007/0233044, 2008/0245371, and 2009/0182325. However, none of thesemedical devices is an ablation catheter system useful for a cardiacablation procedure, nor do any of the devices meet the unique demandscharacteristic of use of an ablation catheter in a catherizationlaboratory setting. In addition, a method and switching mechanisms havebeen developed which are compatible with a number of differentablation/therapy systems to prevent inadvertent therapy delivery andprovide immediate manual control to the operator.

OBJECTS OF THE INVENTION

It is an object of the invention to provide an improved steerableablation catheter system.

It is also an object of the invention to provide an improved steerableablation catheter system where the energy at the distal tip of theablation catheter can be terminated immediately and abruptly.

It is a further object of the invention to provide an improved steerableablation catheter system having a kill switch.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter with a kill switch located in an ergonomiclocation on the catheter handle.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter with a kill switch located in an ergonomiclocation on the handle of the ablation catheter to provide direct andimmediate manual access to abruptly terminate delivery of ablationtherapy.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system with a kill switch located in a cablesupplying ablative therapy.

It is yet a further object of the invention to provide a shorter killswitch attached to a male connector at one end and a female connector atthe other, to interface with an ablation catheter and a connector cable.

It is yet a further object of the invention to provide a kill switchlocated on a remote controller or a joy stick with which the operator ismanually manipulating a remote navigation or robotic system.

It is yet a further object of the invention to provide a specific anduniquely identifiable voice command system that can activate a killswitch mechanism coupled with an ablation therapy delivery system.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system with a foot-operated kill switch.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system where the distal portion of theablation catheter comprises pressure sensors and/or shock absorbingmeans.

It is yet a further object of the invention to provide a system forproviding catheter ablation wherein the system has one or more safetyfeatures to minimize the risk of inadvertent damage to heart tissue,such as, for example, perforation or damage to the conduction system orother cardiac structure.

It is yet a further object of the invention to provide an improvedsystem for delivering treatment or therapy to a patient where a killswitch interrupts the treatment or therapy to minimize or avoid damageto a patient.

It is yet a further object of the invention to provide an improvedsystem for delivering treatment or therapy to a patient in a systemhaving an instrument that is in communication with a hand-operated orfoot-operated control, where a kill switch interrupts the treatment ortherapy to minimize or avoid damage to a patient.

It is yet a further object of the invention to provide a medical systemfor delivering treatment or therapy to a patient that has a kill switchfor interrupting the delivery, where the kill switch can disrupt thedelivery directly or can cause an error message to be generated thatdisrupts the delivery.

It is yet a further object of the invention to provide a medical systemfor delivering treatment or therapy to a patient that has a kill switchfor interrupting the delivery, where the kill switch can disrupt thedelivery of therapy by opening the circuit of one or more feedback orsensed ablation system functions such as temperature, impedance, or thelike.

It is yet a further object of the invention to provide a medical systemfor delivering treatment or therapy to a patient that provides thefunctionality described above via an on/off switch for controllingdelivery of therapy.

It is yet a further object of the invention to provide an on/off switchattached to connectors and a cable or just connectors which attachbetween a medical device and a therapy delivery system.

It is yet a further object of the invention that an entire array ofswitches or cable-switches is created and customized to the particulartype of ablation system, such as cryoablation and/or a particularmanufacturer and/or catheter/device type.

It is yet a further object of the invention to provide a connectorswitch for an ablation system that has a cable and connector as part ofthe catheter ablation device.

It is yet a further object of the invention to provide a connector cableswitch for an ablation system that does not have a cable as part of thecatheter ablation device to permit catheter maneuverability.

It is yet a further object of the invention to provide a longerconnector cable switch to an ablation system in which phrenic nervestimulation is occurring to permit the operator to directly sense andfeel diaphragm contraction and at the same time to be able toimmediately and manually terminate ablation therapy.

It is yet a further object of the invention to provide immediate manualcontrol of a variety of different ablation systems using a connectorsystem interposed between a medical device and it's therapy generator orcontroller.

It is yet a further object of the invention to provide automatic andcomputer controlled control of a variety of different ablation systemsto detect early signs of inadvertent events and immediately terminatetherapy.

It is yet a further object of the invention to provide automatic sensingof phrenic nerve conduction to the diaphragm and immediately cut offtherapy when phrenic nerve conduction and/or diaphragm contraction isslightly diminished by a predetermined value.

It is yet a further object of the invention to provide automatic sensingof cardiac conduction such that early evidence of a change in conductionwould shut off the system before the development of heart block.

It is yet a further object of the invention to provide automatic sensingof early signs of perforation such that a system would immediately cutoff therapy upon detection of those findings.

It is yet a further object of the invention to provide multiple safetyfeatures in a catheter ablation system including (1) the ability toimmediately and manually terminate therapy by the operator and (2) theability to monitor and record contact force and pressure of the cathetertip.

It is yet a further object of the invention to provide multiple safetyfeatures in a catheter ablation system including (1) the ability toimmediately and manually terminate therapy by the operator and (2) theability to absorb and control the contact pressure and/or force of saidcatheter as it makes contact with the heart.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system with a kill switch having abattery-operated timer to limit use of the kill switch.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system with a kill switch having lights thatindicate when the ablation system has been activated and when theablation system has been deactivated due to the kill switch or otherevent.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system with a kill switch having two or moresensors or buttons to activate the kill switch.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system with a kill switch in a cable andhaving a remote sensor or button for activating the kill switch.

It is yet a further object of the invention to provide an improvedsteerable ablation catheter system with a kill switch where lights onthe kill switch indicate when the ablation system has been activated andwhen the kill switch has been activated to terminate therapy.

These and other objects of the invention will become more apparent fromthe discussion below.

SUMMARY OF THE INVENTION

The term “kill switch” as used herein refers to a switching mechanismthat can immediately and abruptly terminate therapy but cannot initiatetherapy by itself. This is in contrast to an “on/off” switchingmechanism, which has the ability both to initiate therapy on its own aswell as to terminate therapy. Also, the term “kill switch” can refer toa switch or button on a catheter handle or casing as well as to the killswitch system itself.

According to the invention, a medical system for delivering ablativetreatment or therapy has been provided where the delivery of ablationtreatment or therapy can be terminated abruptly and immediately by anoperator to prevent heart block and/or other possible proceduralcomplications. In one embodiment of the invention, a kill switch islocated on or in the handle of a steerable ablation catheter, preferablyin an ergonomic location to provide convenient and easy access by athumb of the operator. Preferably the kill switch is a button that isdepressible and operates to terminate delivery of ablation therapy uponbeing depressed.

Ablative treatment or therapy can be delivered to a patient for severaldifferent purposes. Those purposes include, but are not limited to,cardiac, cardio-vascular, urological, and gynecological applicationswhere tissue would be treated.

A typical ablation catheter handle has deflecting levers or controls onthe handle for steering the distal portion of the ablation catheter.Preferably a kill switch is located on the handle between the deflectinglevers or controls to provide ergonomic thumb access from the catheterhandle controlling hand or finger access from the auxiliary hand. Thislocation is advantageous to permit the direct ablation cathetercontroller the ability to most rapidly terminate the delivery oftherapy.

Preferably a kill switch is located in a place or position such thatother fingers on the handle, besides the thumb, and the auxiliary handcan stabilize the catheter to a position, while still allowing theadditional digit of that hand or the auxiliary hand to depress the killswitch most rapidly and efficiently.

In another embodiment of the invention, a kill switch is positioned on amember integral with the cable that supplies the ablative therapy orenergy. For example, the section, member, or casing containing a killswitch can be an integral part of the cable that supplies the ablativetherapy and that is connected to the ablation catheter handle.Alternatively, the kill switch can be located in a separate member intowhich the cable that supplies the ablative therapy and the ablationcatheter are connected.

In another embodiment of the invention, a kill switch is positionedbetween two connectors which would interface at one end with theablation catheter, and the other end would interface with the connectorcable and/or with the ablation therapy generator.

In another embodiment of the invention, the kill switch of the ablationcatheter system is positioned on a remote controller in which theoperator can have immediate and remote access to immediately terminatetherapy. The kill switch could be between connectors or betweenconnectors and cables and could be remotely triggered by a remotecontroller or computer-based system. In addition, the kill switch couldbe independent and remote and provide signals to the ablation cathetersystem. Or it could be integrated on a remote controller, handlecontroller, computer controller, or joy stick to provide remotenavigation or manipulation of an ablation catheter or otherprocedure-related functions.

In another embodiment of the invention, a specific and uniquelyidentifiable voice command can activate a kill switch mechanism coupledwith an ablation therapy delivery system. The switch could be integratedbetween the catheter and the generator and operate via voice command, orthe switch could operate via a voice controller at or near the generatoror at computer terminal/remote control device/workstation remotely.

In another embodiment of the invention a kill switch comprises a buttonthat is configured so that when an ablation catheter is “hot” orenergized, electricity travels through the cable or the catheter handleto light the button or to activate a light, LED, or visual or audiblealert on or in a casing in the cable or in the catheter handle, so thatthe operator is aware that the catheter is delivering ablation therapy.The button is positioned on or in the casing or ablation catheter handleso that other features of catheter manipulation via manual means are notdisrupted. That is, the operator can easily advance, withdraw, deflect,reverse deflect, and/or rotate the catheter distal portion withoutinterfering with the button function.

A light or audio signal on the cable casing or the ablation catheterhandle may provide immediate feedback to the operator to alert him orher that therapy is being delivered. When the button is pressed and thedelivery of ablation energy is immediately stopped or killed, the lightor audio signal shuts off, an indication that the ablation catheter isno longer ablating.

In another embodiment of the invention, a foot pedal functioning as akill switch is operatively connected to a source of ablative therapy, acable supplying ablative therapy, the ablation catheter, a groundingpatch or element, or a combination thereof. The foot pedal is positionedto be readily accessible by an operator's foot.

The catheter system according to the invention is designed to enhancethe operator's reaction, manually, to prevent or minimize inadvertentdelivery of therapy and related complications during catheter ablation.With respect to cardiac catheter ablation, some of these complicationsinclude damage to the conduction system (heart block), perforation ofthe heart tissue itself, and/or damage to adjacent structures such asthe phrenic nerve, which powers contraction of the diaphragm and helpswith respiration.

In another embodiment of the invention, a kill switch contains adeactivator that deactivates after 8 to 24 hours, making the kill switchnon-functional and thereby ensuring that it is disposable. Thedeactivator could be, for example, a digital timer that is activatedwhen power to the system is initiated or a battery is engaged.

In normal catherization or electrophysiology lab operations, theablation therapy may be initiated from a position at some distance fromthe ablation catheter. This could be at the end of the procedural tableor even in another adjacent or distant control room. Such distantlocations may include a generator/control console, remote control,remote controller/controller computer terminal, or the like. The killswitch only becomes engaged when the ablation therapy has been activatedor enabled; it is not otherwise operable. Preferably there will be analert mechanism such as a light or LED on or around a kill switch buttonwhen the ablation therapy has been energized and is well into the distaltip of the ablation catheter. In one embodiment, depressing the killswitch button can open up the circuit (normal closed, once depressed thecircuit is an open kill switch), terminating the ablation therapy, andshutting off the light. The ablation therapy may only be re-initiatedwhen the technician or nurse restarts the radiofrequency generator orlaser, at which time the kill switch or alert mechanism, or both, willbe reset. Alternatively, a “normal open kill switch” could also functionsuch that therapy could only be delivered if the kill switch isactivated by pushing a button and releasing said button would thenterminate therapy.

In another embodiment of the invention, the distal end of an ablationcatheter comprises pressure sensors and compressible, shock absorbingmeans, to minimize the chance of perforation or internal damage. Theshock absorbing material, such as small springs (or an elastic/flexibleablation contactor), is positioned proximal to the distal electrode.Pressure sensors positioned on or near the proximal surface or edge ofthe distal electrode measure the forces exerted on the myocardium by thedistal section of the ablation catheter.

In another embodiment of the invention, the ablation catheter systemwill contain at least two safety mechanisms, including anoperator-operated manual kill switch and a pressure/force controllingsystem to optimize the safety to the patient.

In another embodiment of the invention, the ablation system will provideautomatic detection capabilities to detect at least one early sign ofinadvertent therapy such as phrenic nerve injury, perforation, and/orheart block with the ability to immediately terminate therapy.

There are a variety of kill switches which could be employed in concertwith an ablation therapy delivery system. The invention described hereincould utilize a myriad of buttons, controls, or switches with indicatorsthat function and/or provide information including LEDs, the flow ofelectricity notification, audible tones, etc. Many of these have beenwell described in the electrical engineering literature. The inventionalso encompasses on/off and kill switches that sense pressure,temperature, or any other parameter.

A normal closed momentary kill switch is one in which the electricalcircuit is opened immediately upon depressing the switch itself(typically in the form of a button, although other configurations mayexist) and the circuit's impedance would become infinite and ablationtherapy delivery would immediately terminate. Once the switch isreleased, that is, not depressed, the circuit would immediately closeand pacing and sensing function from the therapy delivery tip (typicallyan electrode) would be restored. However, the ability to deliverablation therapy could not be re-engaged without turning on therapy atthe generator source itself. This type of mechanism is ideal forpreventing inadvertent delivery of ablation therapy and pacing/sensingfunction from the therapy electrode or electrodes would only be“momentarily” disrupted during the kill switch deployment andimmediately restored upon release of the switch. As above, normal openmomentary kill switches could also function in a manner that therapydelivery could only occur with the switch engaged, and therapytermination would occur with release of said switch.

In a preferred embodiment of the invention the kill switch is amechanical kill switch which is normally in the closed position and,when depressed, transiently stays open. Said kill switch is capable ofwithstanding 100 watts and 500 kHz with a typical 250 vac and 3 amprating.

Alternatively, a multi-function switch could control the opening andclosing of the kill switch upon each depression or contact. The downside of the latter configuration is the potential for longer disruptionof the distal therapy sensing and pacing function. A parallel circuitcould separate out therapy delivery disruption from pacing and electrodesignal recognition/sensing (i.e., kill switch functionality withoutdisrupting pacing or sensing). In fact, the kill switch can deliver asignal to alter impedance and stop ablation therapy delivery without anyeffect of sensing or pacing. It can be envisioned that there arenumerous ways of providing effective and immediate operator control overtherapy delivery via use of a kill switch without having any significantimpact (if at all) of electrode functionality (i.e., pacing andelectrode signal visibility or sensing). In addition, the kill switchcould sense some other function or feedback required for effectivetherapy delivery and/or function, if this signal is disrupted via thekill switch an error could be detected at the generator and therapyterminated. This is the case with the Medtronic Cardiac CryoAblationSystem (ARCTIC FRONT®) in which liquid nitrogen is delivered to aballoon/or catheter to freeze tissue. If the electrical connector andsome of its functions are disabled (i.e., open circuit) the CryoConsoleimmediately shuts down. All of these are encompassed in the inventiondescribed herein.

In another embodiment of the invention, a kill switch could bepositioned on a remote control in order to remotely terminate therapy.This could either be a stand-alone remote control or one that isintegrated into a remote control station or remote controller in orderto provide control over other aspects of the ablation procedure. It iseven possible for this switch mechanism's remote control to beintegrated with the controller for remote navigation of an ablationcatheter. The kill switch could be located on a handle controller or joystick or computer controller distal to the catheter manipulator.Alternatively, the kill switch can open the circuit of any signal thatis critical to therapy delivery and send an error message to the signalor therapy generator, console, computer (CPU), or the like, in order toterminate the delivery of any type of therapy.

In another embodiment of the invention, the kill switch can create anerror signal terminating therapy, for example, by changing impedance,disrupting feedback communications, or the like. Alternatively, a killswitch on a ground cable would interrupt the grounding function andcause an error message to be sent that would disrupt the therapy.

In another embodiment of the invention, an on/off switch can function ineach of the above embodiments, in a similar manner and/or configurationas the kill switch configurations above. The “on” component of theswitch could be configured to sense human contact prior to being engagedthereby preventing inadvertent therapy by being dropped or leanedagainst. Other implementations of said on/off switch similar to the killswitch above in a connector-cable or as a connector-switch could providemanual access to the operator in a similar fashion customized to avariety of different ablation systems and manufacturers.

Electricity is necessary to travel from point A to point B to provideablation therapy (either directly as is the case with radiofrequencyenergy, or indirectly, as is a controlling or feedback signal monitoringballoon pressure and temperature in a cryoablation balloon). If aswitching mechanism such as a kill switch were interposed between theelectrical circuit of point A to point B, it could be configured suchthat the circuit is normally closed and momentarily manually depressingthe switch would open up the circuit and thereby prevent electricityfrom proceeding, thereby terminating therapy (normally closed momentarykill switch). Alternatively, the kill switch could be configured to benormally open and depressing said switch would be necessary prior todelivery of ablative therapy initiated by traditional means (normallyopen momentary kill switch). Releasing the depressed kill switch in thislatter configuration would terminate therapy.

In both examples, the kill switch, unlike an on/off switch is incapableof turning on therapy itself. Therefore, the unique application of thekill switch to catheter ablation is its ability to prevent inadvertenttherapy delivery. You cannot step or accidentally press a kill switchand turn on ablation therapy. The kill switch described herein is amechanical momentary kill switch. The momentary kill switch may bepreferable for the application of terminating ablation therapy, but itis not absolutely necessary. The kill switch can be depressible and lockinto position. A tested catheter handle version contained such a switchthat, once depressed, held the closed position, and when depressedagain, opened the circuit to terminate therapy. Each depressionmechanically reset the circuit accordingly.

Other types of configurations could include an automatically triggeredkill switch based on a sensed algorithm for early detection of adverseevents such as phrenic nerve injury. The phrenic nerve could bestimulated and phrenic nerve conduction and/or diaphragm contractioncould be recorded. A predetermined minimal change in threshold couldtrigger the kill switch to automatically terminate therapy in thisinstance. Similarly, early signs of perforation and/or changes inconduction could trigger the kill switch to terminate therapy therebyreducing the chance of a significant complication. In addition, the killswitch or an on/off switch could function via a remote controller (usinga transmitter/receiver configuration such as a television remote controlusing infrared or radio wave signals). Alternatively, these switchescould also function via voice or sound command and can have somepreprogrammed actuators, signals, and voice programs.

Regardless of whether the switching mechanism is an on/off switch ofkill switch many variations are possible, including a depressiblebutton, toggle switch, temperature or infrared sensor, or switch button,for example. For standard radiofrequency a switching mechanism wouldtypically need to be rated for at least 100 Watts at 500 kHz with a 250vac/3 amp rating. Error signals and other types of sense signals mayhave different and perhaps less energy requirements to functionappropriately. In addition, standard radiofrequency ablation typicallydelivers therapy from the distal ablation electrode to a groundingpatch. A single pull kill switch may operate effectively interposedbetween the conductor or wire that goes to that electrode. However, morecomplicated and future ablation systems may deliver energy through morethan one electrode and a multiple pull kill switch would be necessary todisrupt all therapy immediately. The same goes for critical errorsignals necessary for feedback and surveillance of non-radiofrequencyenergy (e.g., cryoablation). These signals may require more than onepull (or one open conductor) to shut down therapy. In addition, it isconceivable that the switching mechanism itself can produce its ownerror signal and disrupt the controller/generator and terminate therapyas well. A number of different switching mechanisms and configurationscan achieve the goal of this novel therapy intended as a more efficientmeans of rapidly terminating therapy and avoiding unnecessarycomplications.

In another embodiment of the invention, in an improved ablation cathetersystem comprising a longitudinally extending catheter having a proximalend and a distal end, a handle attached to the proximal end of thecatheter, a mechanism at the distal end of the catheter for deliveringablation therapy to a desired location, such as tissue, and a generatoror controller of ablation therapy in communication with the handle, thehandle and the distal end of the catheter, or the handle, the catheter,and the distal end of the catheter, the ablation catheter systemcomprises a switching mechanism which is capable of causing abrupttermination of delivery of ablation therapy by manual, automatic,remote, or voice-operated operation.

In another embodiment of the invention, the switching mechanism ispositioned between the ablation catheter distal tip and the generator orcontroller of ablation therapy, including on or in the therapy-producinggenerator or controller.

In another embodiment of an ablation catheter system of the invention,the kill switch is interposed on or in communication with one or moreconductor wires contained within the ablation catheter, an electricalconnector cable, a separate device connected between the catheter and atherapy-producing generator or controller, or the therapy-producinggenerator or controller.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is an on/off or kill switch which is containedon and/or within the handle, which is in or in communication with aconnector cable, a separate device connected between the catheter andthe therapy-producing generator or controller, or the therapy-producinggenerator or controller.

In another embodiment of an ablation catheter system of the invention,the switching mechanism comprises wires, connectors, a switch, and aprotective enclosure to permit operation on a sterile medical field.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is interposed on or in communication with atleast one conductor wire contained within the catheter and a cable whichleads from the catheter to a therapy-producing generator or controllerand which operation of the switching mechanism permits therapy,terminates therapy, or permits and terminates therapy.

In another embodiment of an ablation catheter system of the invention,the switching mechanism comprises a depressible button, a touchsensitive switch, a toggle switch, a pressure- or temperature-sensitivesensor, or the like.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is positioned between steerable levers on thehandle and/or catheter body to provide ergonomic thumb, finger, or thumband finger access.

In another embodiment of an ablation catheter system of the invention,wherein the determination of whether a switching mechanism is to bepositioned on the handle of the catheter, in a cable having a distal endthat is inserted into the handle or rigid portion of a handle of acatheter, in a short cable segment to be attached to the proximal end ofa cable extending from the handle of a catheter and the proximal end ofa cable from a therapy generator or controller, or in a long cablesegment to be attached to the proximal end of a cable extending from thehandle of a catheter and the proximal end of a cable from a therapygenerator or controller, is based upon factors such as the design andconfiguration of the catheter, the ablation therapy, and the location ofthe site to be ablated.

In another embodiment of an ablation catheter system of the invention,wherein the location of the switching mechanism as well as its mode ofincorporation into the catheter ablation system is determined byaccessibility to a manufacturer's platform, the type of catheter and itsdesign and presence or absence of a built in cable at the end, the typeof procedure, position of the patient's catheter access site, theoperator's position, and the operator's necessity to immediately monitorfor adverse effects of the therapy on the patient.

In another embodiment of an ablation catheter system of the invention,the design, configuration, and position of said switching mechanism andits application is determined by the type of procedure, type of catheterand its design, catheter access point, position of the patient, positionof the operator, maneuverability of the medical device (i.e., catheter),as well as the operators ability to monitor for inadvertent therapywhile performing said procedure. Such a design may consider a longercable with the switch mechanism positioned more proximal to the operatorsuch that the operator could perform a cryoablation procedure from thegroin and have access to the switch in order to manually feel thecontraction of the diaphragm during phrenic nerve stimulation and at thesame time have manual control of the therapy with the ability toimmediately shut off therapy if diaphragm contraction (or its surrogate)diminishes in order to avoid permanent phrenic nerve damage. A shorterconnector switch could attach directly to a Boston Scientific BLAZER®radiofrequency ablation catheter since that device already hasapproximately 8 inches of cable at the end of said catheter permittingmanual manipulation. Other radiofrequency ablation catheters such as theMedtronic RF ablation catheter, the Johnson & Johnson Biosense WebsterTHERMOCOOL® ablation catheter, and the St. Jude Medical SAFIRE TX™ablation catheter have handles which terminate with just a connector.Each of these handles has an integral plug for receiving a connectorfrom a cable or device. A switching mechanism device, which includesenough of a cable, would help such that those catheters could be easilyrotated without making manipulation awkward.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is positioned in a long cable segment to beattached to the proximal end of a cable extending from the handle of acatheter and the proximal end of a cable from a therapy generator orcontroller for cryoablation, so that an operator can operate theswitching mechanism and feel a patient's diaphragm contractions toprevent phrenic nerve paralysis.

The variety of connectors and cables useful with ablation cathetersaccording to the invention means that one carrying out the inventionherein will have to select the appropriate cable, device, and/orconnector to match up to the handle of the ablation catheter used. Theablation catheter described above which terminate without any built-incable may require a cable plus switching mechanism to permit cathetermaneuverability. The Boston Scientific ablation catheter which hasapproximately 8 inches of cable built in at the end can utilize aconnector switch with or without a cable. A longer cable may be requiredfor a cryoablation procedure performed from the groin, if the operatoris to feel diaphragm contraction force while at the same time feeling aswitch attached to a catheter. A remote control could trigger the switchmechanism itself. Such a control could have a transmitter/receiverconfiguration and operate the switching mechanism in a catheter,connector, cable, generator, computer controller, or combinationthereof.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is located so that other fingers on the handleand the auxiliary hand can stabilize catheter positioning while stillallowing an additional digit of that hand or the auxiliary hand todepress the switching mechanism most rapidly and effectively.

In another embodiment of an ablation catheter system of the invention,the location of the switching mechanism as well as its mode ofincorporation into the catheter ablation system are determined byaccessibility to a manufacturer's platform, the type of catheter and itsdesign and presence or absence of a built in cable at the end, the typeof procedure, position of the patient's catheter access site, theoperator's position, and the operator's necessity to immediately monitorfor adverse effects of the therapy on the patient.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is positioned in a long cable segment duringcryoablation, so that an operator can manually operate the switchingmechanism and feel a patient's diaphragm contraction at the same time toprevent phrenic nerve paralysis.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is in the most appropriate place to allow anoperator to both manually perform an ablation procedure and to manuallyterminate therapy.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is positioned between two connectors and wiresin either a cable plus enclosure or just an enclosure, all intended totransmit and/or control ablation therapy.

In another embodiment of an ablation catheter system of the invention,the switching mechanism can be engaged only after ablation therapy hasbeen initiated from the therapy-producing generator and/or computercontroller.

In another embodiment of an ablation catheter system of the invention,the switching mechanism has an alert function.

In another embodiment of an ablation catheter system of the invention,the switching mechanism can receive a signal from a remote controller toterminate therapy.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is voice-, touch-, or sound-activated and iscoupled either directly or remotely to the ablation therapy deliverysystem.

In another embodiment of an ablation catheter system of the invention, areceiver has been programmed to recognize an operator's voice, a certaincommand or commands, or a combination thereof.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is controlled remotely, wired or wirelessly, topermit immediate and remote therapy termination.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is a kill switch that either (1) is normally aclosed circuit and when the switch is engaged it opens the circuit,forcing the ablation catheter system to shut off its therapy, and thencloses immediately, thereby restoring full functionality of the systemwithout re-initiation of therapy delivery or (2) is normally an opencircuit which requires the switch to be engaged such that the circuit isclosed thereby permitting the transmission of ablation therapy, whereasdisengaging said switch immediately terminates therapy.

In another embodiment of an ablation catheter system of the invention,the kill switch can operate as a fixed switch such that engaging theswitch performs one function such as closing an electrical circuit inorder to permit ablation therapy delivery and re-engaging said switchopens an electrical circuit thereby terminating therapy; or a momentarymode such that an electrical circuit is either open or closed as long asthe switch is manually engaged.

In another embodiment of an ablation catheter system of the invention,the switching mechanism works directly through the therapy generator orcontroller.

In another embodiment of an ablation catheter system of the invention,the switching mechanism is a kill switch that momentarily opens, forcingthe ablation catheter system to shut off its therapy, and then closesimmediately, thereby restoring full functionality of the system withoutre-initiation of therapy delivery.

In another embodiment of an ablation catheter system of the invention,the switching mechanism or kill switch comprises parallel circuitry inwhich ablation therapy delivery can be immediately disrupted withoutinterrupting any of the system's electrical capabilities.

In another embodiment of an ablation catheter system of the invention,the switch mechanism is depressible and resettable.

In another embodiment of an ablation catheter system of the invention,in an improved ablation catheter system comprising a longitudinallyextending catheter having a proximal end and a distal ends, a handleattached to the proximal end of the catheter, a mechanism at the distalend of the catheter for delivering ablation therapy, and a source ofablation therapy in communication with the handle, the catheter, and thedistal end of the catheter, the improvement wherein the system has aswitching mechanism and one or more additional safety features tominimize the risk of inadvertent damage to tissue, especially hearttissue.

In another embodiment of an ablation catheter system of the invention,shock absorbing materials are interposed between the distal tip of thecatheter and the catheter to help absorb the contact force and minimizepressure delivered to tissue and the risk of inadvertent damage.Alternatively, the tip may be made of an elastic and or flexiblematerial in order to help absorb and cushion the contact.

In another embodiment of an ablation catheter system of the invention,one or more contact sensors are interposed between the ablation therapydelivery tip and the absorbent material to measure the degree ofcontact.

In another embodiment of an ablation catheter system of the invention,one or more contact sensors measure pressure, force, or both pressureand force and the operator has direct manual access to terminatetherapy.

In another embodiment of an ablation catheter system of the invention,haptics are coupled to the handle to provide feedback to an operator asto the amount of contact pressure that is being delivered to the tip ofthe ablation delivery system within the human body.

In another embodiment of the invention, a system for preventinginadvertent damage to heart tissue comprises an immediately accessiblekill switch and features to detect and minimize excessive forcedelivered to the tip of an ablation catheter system within the heart.

In another embodiment of an ablation system of the invention, a systemfor preventing inadvertent damage to the heart and/or circulatory systemand/or pericardial space during delivery of ablative treatment ortherapy comprises a plurality of safety features, including (1) animmediately accessible on/off or kill switch and (2) one or more forceor pressure sensors to detect and minimize excessive force delivered tothe tip of an ablation catheter system.

In another embodiment of an ablation system of the invention, the systemis an operator-controlled system which permits the operator to haveimmediate manual control over (1) the amount of force applied to the endor ends of an ablation system and (2) permitting ablation therapy,terminating ablation therapy, or permitting and terminating ablationtherapy.

In another embodiment of the invention, a medical device which fastensover a first connector and a connectable second connector of aconnection cable linked to a medical device for delivering medicaltreatment or therapy, contains a mechanism for easily separating thefirst and second connectors and thereby interrupting treatment ortherapy.

In another embodiment of a medical device of the invention, the medicaldevice also permits easy reconnection of the connectors.

In another embodiment of the invention, a rapid cable connect/disconnectdevice for immediate separation of a male cable connector and a femalecable connector, comprises a component which grasps both connectors,maintains alignment of the connectors to one another, unlocks anylocking mechanism, and separates said connectors, and is also capable ofmechanically reconnecting or re-coupling the cable connectors in analigned manner to restore continuity.

In another embodiment of the invention, a device can be used in concertwith an ablation catheter system such that rapid cable disconnectionresults in termination of ablation therapy to minimize damage frominadvertent therapy delivery and rapid cable reconnection can restorefull functionality of the ablation catheter system.

In another embodiment of the invention, a switching mechanism for usewith an ablation catheter system comprises: a first wired or wirelesscomponent for direct manual activation, which is capable of beingattached to or placed adjacent to an ablation catheter handle, and asecond wired or wireless component coupled to the first component toreceive, transmit, or receive and transmit a switching signal generatedby the first component, to provide direct manual control of the deliveryof ablation therapy.

In another embodiment of the invention, the first component can beattached to the catheter handle with a stretchable sleeve, a clip, aconnector, or sterile adhesive.

In another embodiment of the invention, a rapid cable connect/disconnectdevice having a kill switch provides for immediate connection orseparation of a male cable connector and a female cable connector. Therapid cable connect/disconnect device comprises a component with maleand female receptors which grasp the respective female and male ends ofthe connectors, maintains alignment of the connectors to one another,and optionally unlocks any locking mechanism. The female receptor of therapid cable connect/disconnect device engages the male connector and themale receptor of the rapid cable connect/disconnect device engages thefemale connector, so as to separate the connectors, and the rapid cableconnect/disconnect device is also capable of mechanically reconnectingor re-coupling the cable connectors in an aligned manner to restorecontinuity.

In another embodiment of the invention, a rapid cable connect/disconnectdevice with a kill switch can be used in concert with an ablationcatheter system such that rapid cable disconnection results intermination of ablation therapy to minimize damage from inadvertenttherapy delivery and rapid cable reconnection can restore fullfunctionality of the system.

In another embodiment of the invention, a device for immediateseparation of first and second cable connectors comprises a firsttubular or substantially tubular member that is capable of encirclingand grasping the first cable connector, a second tubular orsubstantially tubular member that is capable of encircling and graspingthe second cable connector, and a bridge member connecting the first andsecond tubular or substantially tubular members, wherein, when a portionof the bridge member is pushed downward, a latch disengages and thetubular or substantially tubular members move away from each other andcause the cable connectors to disengage or disconnect.

In another embodiment of the invention, the device facilitates easyreconnection of the first and second cable connectors.

In another embodiment of the invention, an on/off switch or kill switchis positioned between two connectors in a component. The component canbe positioned relative to an ablation catheter handle based on one ortwo cable connectors of varying lengths. The component may be attachedto two variable length cable connectors, one of which is attacheddirectly to the ablation catheter handle, or, dependent upon which modelablation catheter is used, the component may be attached directly to theproximal end of the handle of the ablation catheter. The lengths of thecable connectors may vary depending upon where the operator wants thecomponent (with the on/off or kill switch) to be positioned relative tothe ablation catheter handle. If there is a cable connector between theablation catheter handle and the switching component, that switchingcomponent would preferably be disposable, and the cable connectors couldeach be reusable/resterilizable. However, it is possible that theswitching component and cables could be either disposable orreusable/resterilizable.

In another embodiment of the invention, a component comprising a killswitch is configured for dual use, that is, to be convertible frommanual to foot operation. More particularly, the component would beconfigured so that it could be functionally connected to an ablationcatheter and be positioned within the sterile field for manual operationby the operator to kill ablation function and so that it couldalternatively be positioned for foot operation. For example, thecomponent could operate on a sterile field in a first mode of operationas a manual kill switch (with a kill switch on the top surface of thecomponent for manual operation), and the component could operate and bepositioned in a second mode such that the switch component could beopened up and placed on the floor (non-sterile) such that the foot couldcontrol a pedal inside the component in order to trigger the kill switchand terminate therapy.

In another embodiment of the invention, an on/off switch or kill switchcan be attached directly onto an ablation catheter handle via suitablemeans, such as a sterile adhesive, a clip, or a sleeve (that would slideover the front or back of the catheter handle). If the switch isconnected to the ablation therapy system via a connector cable—eithercontained therein or as a separate device interposed between connectorcables—the switch could double back toward the catheter handle and clipon, slide on, or adhere to the handle by a number of means to thecatheter handle such that the switch itself functions on the handle.

In another embodiment of the invention, a connector cable could beconfigured such that all of the wires are contained within the connectorcable and the wire or wires necessary for switching off therapyseparately branch off to connect to an on/off or kill switchingmechanism. That switching mechanism can be attached to an ablationcatheter handle in a number of different ways, such as by adhesive, asleeve, or a clip. The input and output wires of the switching mechanismcould be contained within a thinner sleeve that could reach the ablationcatheter handle and adhere to the ablation catheter handle to permitcatheter manipulation and have the switching mechanism on the ablationcatheter handle itself. The connector cable will consist of a thickerand stiffer cable at its proximal end which connects to a generator orcontrol console and a distal member containing a thinner, more flexiblewiring to the switching mechanism which can be placed on the ablationcatheter handle. The separate switching mechanism could essentially be athin wire that can extend from the end of the connector cable proximalto the catheter and easily attach to the ablation catheter handlewithout tangling during manipulation and permit easy access to theswitch on the ablation catheter handle to terminate therapy manually.

In another embodiment of the invention, a connector cable looks like aregular cable and has a separate terminus for a thinner switchingmechanism which could attach to the connector cable. This mechanism ifnot engaged would allow the connector cable to operate like a regularconnector cable, but if the switching mechanism is attached, it then hasthe ability to terminate therapy. The switching mechanism can operateoff the handle or it can attach directly to the ablation catheterhandle.

In another embodiment of the invention, a switching mechanism attachesdirectly onto an ablation catheter handle. The switching mechanism canlook similar to FIG. 1A such that it can be placed in an easilyaccessible position on the ablation catheter handle to provide easyergonomic access to the switching mechanism to easily terminate therapy.The switching mechanism itself can be wireless (i.e., no direct wiresterminate from the switch directly into the ablation catheter or itsconnector cable). However, the switching mechanism can adhere to theablation catheter by a number of ways, such as adhesive, a clip, or aflexible stretchable sleeve, and can terminate therapy by transmitting asignal to the receiver switching mechanism incorporated in a connectorcable, separate device, generator, console, or computer controller.Alternatively, the switching mechanism can create a signal which couldinterrupt therapy by creating an error signal. For example, astretchable sleeve slid over the proximal end of the handle may containmany turns of an electrical coil. When the sleeve is depressed(engaged), it could send a current throughout the coils to create anelectrical current through the ablation wires contained in the handlevia inductance, changing the signal enough that an error could bedetected by the generator or controller console and terminate therapy.Other types of error and/or jamming signals could also terminatetherapy. In essence the method provides a free standing, sterile methodto achieve an on/off switch or kill switch functionality with a wirelessmechanism, which can adhere or attach to the ablation catheter handle.

In another embodiment of the invention, a sealed reusable connectorcable could contain a kill switch which looks and feels like a morestandard cable (though it may have a bulge for the separate kill switchmechanism). This switch/cable could be reusable and resterilized (aswell as disposable). This switching mechanism contained within the cablehas a receiver function. A separate sterile disposable switch whichcould clip to the handle, slide over the front or back as an elastic orstretchable sleeve, or attach to the handle by some other adherentmechanism and could serve as a transmitter switch which when activated(i.e., depressed for example) it would send a signal to the transmitterand terminate therapy. In addition, the kill switch receiver could becontained within the ablation generator, console, or computercontroller.

In another embodiment of the invention, an on/off or kill switchmechanism could be built-in to a device which attaches to or rides overthe proximal end of an ablation catheter handle which terminates withonly a connector and no cable. Examples of such catheters includeMedtronic's RF catheter, St. Jude Medical's SAFIRE catheter, andBiosense Webster's THERMOCOOL catheter. The device could comprise aseparate component that (1) has an integral switching mechanism, (2)plugs into the proximal end of the ablation catheter handle, and (2) hasa male or female receptacle for receiving a connector from a cable.Alternatively, the device could comprise the distal end of a cable that(1) has an integral switching mechanism to attach to the ablationcatheter handle and (2) plugs into the proximal end of the ablationcatheter handle. In essence, this device can permit the switchingmechanism to appear as if it is part of the ablation catheter handleitself.

In another embodiment of the invention of an improved ablation cathetersystem comprising a longitudinally extending catheter having a proximalend and a distal end, a handle attached to the proximal end of thecatheter, a mechanism at the distal end of the catheter for deliveringablation therapy to a desired location, and a generator or controller ofablation therapy in communication with the handle and the distal end ofthe catheter, the improvement comprises a switching mechanism which iscapable of causing abrupt termination of ablation therapy by manualoperation, wherein the switching mechanism is positioned between thegenerator or controller of ablation therapy and the catheter handle, andwherein the switching mechanism has a button or other activation meansto terminate ablation therapy and one or more lights that reflect thestate of the ablation catheter system.

In another embodiment of the invention, a second, separate button orother activation means is connected through a wire or cable to theswitching mechanism, which second button or other activation means iscapable of being placed in an ergonomic position on the handle of theablation catheter in an easily accessible position to provide immediatemanual control by the catheter operator to terminate therapy.

In another embodiment of the invention, a second, separate button orother activation means is connected through a fixed wire to theswitching mechanism, which second button or other activation means iscapable of being placed in an ergonomic position on the handle of theablation catheter in an easily accessible position to provide immediatemanual control by the catheter operator to terminate therapy.

In another embodiment of the invention, a second, separate button orother activation means is connected through a removal wire to theswitching mechanism (much like a headphone jack), which second button orother activation means is capable of being placed in an ergonomicposition on the handle of the ablation catheter in an easily accessibleposition to provide immediate manual control by the catheter operator toterminate therapy.

In another embodiment of the invention, a sleeve or stretchable sleeveor rubber/foam handle cover is configured to fit over or around acatheter handle and provide enhanced grippability and/or comfort. Saidsleeve or cover also provides an encasement for a second, separatebutton or other activation means attached to a cable-mounted switchingmechanism and attached to the distal portion of an ablation catheter.

In another embodiment of the invention, a sleeve or stretchable sleeveor rubber/foam handle cover is configured to fit over a catheter handlesuch as the sleeve or cover has a button or other activation meanscontained within it in order to terminate the ablative therapy.

In another embodiment of the invention, a switching mechanism for anablation catheter system comprising a longitudinally extending catheterhaving a proximal end and a distal end, a handle attached to theproximal end of the catheter, a mechanism at the distal end of thecatheter for delivering ablation therapy to a desired location, and agenerator or controller of ablation therapy in communication with thehandle and the distal end of the catheter, comprises:

-   -   a casing having an upper surface and two lateral surfaces;    -   a button or other activation means positioned on the upper        surface; and    -   at least one light to reflect the status of the ablation        catheter system,    -   wherein pushing the button or other activation means terminates        the delivery of ablation therapy.

In another embodiment of the invention, a switching mechanism for anablation catheter system comprising a longitudinally extending catheterhaving a proximal end and a distal end, a handle attached to theproximal end of the catheter, a mechanism at the distal end of thecatheter for delivering ablation therapy to a desired location, and agenerator or controller of ablation therapy in communication with thehandle and the distal end of the catheter, comprises:

-   -   a casing having an upper surface and two lateral surfaces;    -   a button or other activation means positioned on the upper        surface; and    -   at least two lights to reflect the status of the ablation        catheter system,    -   wherein one of the lights is red and the other is green,    -   wherein the normal button function when electricity flows        through the switch and the green switch light is        activated/illuminated,    -   wherein pushing the button or other activation means terminates        the delivery of ablation therapy and the red switch light is        activated/illuminated,    -   wherein inactivation of the switch is indicated by neither light        being illuminated.

In another embodiment of the invention, the switching mechanism alsocontains a digital timer with a predetermined shutoff period.

In another embodiment of the invention, the timer is powered by abattery within the casing or power from the ablation catheter system.

In another embodiment of the invention, the timer starts when thebattery or the ablation system is activated.

In another embodiment of the invention, the timer can be restarted butnot reset.

In another embodiment of the invention, a method of controlling the useof a medical product used in a surgical or clinical procedure, comprisesinserting into the medical product a digital timer that is set to apredetermined time period of operability, that begins timing when thetimer is activated, and that cannot be reset.

In another embodiment of the invention, the digital timer is powered bya battery and begins timing when the battery is activated.

In another embodiment of the invention, the digital timer is powered bythe medical product and begins timing when the medical product isactivated.

In another embodiment of the invention, a method of controlling the useof a medical product used in a surgical or clinical procedure, comprises

-   -   providing a medical product that comprises a digital timer set        to a predetermined time period of operability that begins timing        when the timer is activated, that deactivates the medical        product at the end of the predetermined period, and that cannot        be reset once started;    -   recovering the used medical product;    -   resetting or replacing the digital timer;    -   sterilizing and repackaging the recovered product; and    -   selling the recovered product at a cost less than when new.

Reuse of manufactured ablation catheters has been problematicspecifically as it relates to the quality control of the ablationcatheter and its electronic components (temperature sensors, electrodes,connectors, etc.). There is a need to have better quality control andprevent haphazard reuse of said catheters. In addition, there is a needto improve on the functionality and manual control contained within theablation catheter itself. It is intuitive that the switching mechanismshould be ideally located within or on the ablation catheter and in anergonomic location such as the distal component, which is in the frontof the catheter near the normal location of the thumb when the catheterhandle is gripped. By placing the switching mechanism in the ablationcatheter, it would be important to prevent random resterilization inorder to assure the functionality of said catheter as well as theperformance of the switch.

Therefore, a routine ablation catheter could contain a battery and apowered timer which could limit catheter operation time. The battery,could have a protector or tab or piece of insulation between itself andits electrical connector. Once the catheter is pulled out of its sterilepackaging, said insulation could be remove or dislodged and the batteryengaged directly with its connector in order to initiate a digitaltimer. The timer could function for a predetermined amount of time, andafter which the catheter itself would become nonfunctional. It could beimpossible for the facility that purchased said catheter to reset theclock or timer without going back to the original manufacturer. Thebattery could have a limited lifespan (say for example 8 hours and thetimer may last for a similar amount of time or even up to 24 hours).Only the manufacturer could potentially refurbish, replace, andresterilize, reset, and reuse the original ablation catheter and/or itscomponents and resell them at a discount back to the original facilityor some other facility.

In addition, an ablation catheter if powering a timer via a battery,could also power a built-in switching mechanism such as a kill switch.The battery could also power one or more LEDs, which could display thefunctionality of said switch in the device. For example, a green LEDcould indicate that ablation therapy is turned on and being delivered; ared LED could indicate that the ablation therapy is turned off.

Each and every functionality and component described above could beoperational all within or on a standard ablation catheter and togetherwould prevent routine and random resterilization by outside facilitiesand/or the operator's medical institution. Only the originalmanufacturer would be able to reset the timer contained within thedevice, replace the battery, evaluate each and every component,resterilize and repackage and resell said catheter at a discount.Overall, this would provide a significant quality control measure aswell as a potential cost saving to the facility.

It is understood that this exact functionality as described in the aboveparagraphs could also be applied to a separate switching mechanismpositioned between the ablation catheter and the ablation therapygenerating or producing system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an oblique view of the handle of an ablation catheter, whichhandle represents an embodiment of the invention;

FIG. 1B is a lateral view of the handle shown in FIG. 1A;

FIG. 2 is a schematic representation of an embodiment of the inventionwhere a kill switch is positioned in a member that can be positionedbetween a cable supplying ablative energy and an ablation catheter;

FIG. 3 is a schematic representation of an embodiment of the inventionwhere a kill switch is positioned in a cable supplying ablative energy;

FIG. 4. is a schematic representation of a foot pedal that can act as akill switch;

FIGS. 5 and 6 are schematic representations of the distal end of anablation catheter according to the invention;

FIG. 7 is a schematic of the kill switch on a remote handle controllerwhich can remotely manipulate an ablation catheter and/or system;

FIG. 8 shows a schematic diagram of voice command activated kill switchmechanism for remotely activating the kill switch with a precise andlearned verbal command;

FIG. 9 is a view of an end of a plug for a radiofrequency cable usefulaccording to the invention;

FIGS. 10A and 10B are schematic drawings of a simple mechanicaldis-connector according to the invention;

FIG. 11 is a schematic drawing of a variation of the manner in which akill switch can be positioned on and in communication with a catheterhandle and a cable;

FIGS. 12A and 12B are schematic drawings of flexible sleeves that can bepositioned over catheter handles;

FIG. 13 is a schematic drawing of another embodiment of the inventionwhere a kill switch can be positioned on and in communication with acatheter handle and a cable;

FIG. 14 is a schematic representation of on/off or kill switch that canbe positioned on a catheter handle;

FIGS. 15A and 15B are schematic lateral and top views of an alternativeto the embodiment of the invention shown in FIG. 3;

FIG. 16 is a schematic drawing of a variation of the embodiment of theinvention shown in FIGS. 15A and 15B;

FIG. 16A is a detail of the schematic drawing shown in FIG. 16;

FIG. 17 is a schematic drawing of a second kill switch button usefulaccording to the invention; and

FIG. 18 is a schematic drawing of a handle gripper useful according tothe invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention can perhaps be more appreciated from the embodiments ofthe invention set forth in the drawings. In FIGS. 1A and 1B, a steerableablation catheter handle 2 has a proximal portion 4 and a distal portion6. Distal portion 6 engages a distally extending ablation catheter 10,and a pivoting lever mechanism 12 steers ablation catheter 10. A reddepressible button 14 is positioned on the upper surface 18 of handle 2.When ablation energy enters handle 2 from proximal cord or cable 20,button 14 lights up.

In the embodiment of the invention set forth in FIG. 2, a connector 30attached to a cable 32 from an ablation therapy supply (not shown) canbe connected to a first, male connector 38 of a member 40 having amomentary mechanical or digital kill switch 42 with a button 43. Asecond, female connector 44 of member 40 can be connected to connector46 attached to a cable 50 of an ablation catheter (not shown) or to acatheter such as the Biosense Webster THERMOCOOL catheter that comprisesa receptacle for connector 44 at its proximal end (not shown).

With regard to kill switch 42, when kill switch 42 is in a rest orclosed position, that is, button 43 extends away from the surface, thecircuit between cable 32 and cable 50 is closed. Pushing button 43causes switch 42 to open the circuit between cable 32 and cable 50,disrupting therapy. Switch 42 can be rated at, for example, 250 vac and3 amp. The lengths of cables 32 and 50 can be varied dependent uponfactors such as the desired placement of member 40, the catheter used,or the positions of other equipment.

Member 40 may comprise a clam shell outer casing that is sealed andwater resistant. Alternatively, the casing could be injection molded.Preferably member 40 has insulated copper wire 48 (dotted lines)connecting connector 38, switch 42, and connector 44. Connector 44 maybe, for example, a Redell 10-pin connector, which would be compatiblewith the Boston Scientific BLAZER catheter. Other pin connectors may bechosen to be compatible with other catheters available from, forexample, Biosense Webster (Johnson & Johnson), Medtronic, and St. JudeMedical.

FIG. 3 represents an alternative embodiment where a cable 52 from anablation therapy source (not shown) comprises a section 54 with a killswitch 56. A connector 60 attached to cable 52 is capable of connectingto a connector 62 of a cable 64 attached to an ablation catheter (notshown). Catheters such as St. Jude Medical catheters, Medtronic RFablation catheters, and Biosense Webster catheters that do not have anycable extending as part of the ablation catheter may benefit from aconnector-cable-kill switch-cable-connector configuration rather than astraight connector-kill switch-connector configuration to provide morecatheter maneuverability rather than a longer stiffer handle. Thecustomer could choose and select the particular length of cable,location, and/or configuration that best meets their needs. TheMedtronic Cardiac CryoAblation catheter (ARCTIC FRONT) to freezepulmonary veins on the right side could be connected to a longercable-kill switch-cable system such that the operator could reach andfeel diaphragm contraction during phrenic nerve stimulation while at thesame time having the other hand on the kill switch to immediately detectany adverse effects to the phrenic nerve and immediately terminatetherapy.

In the embodiment of the invention shown in FIG. 4, a foot pedal 70 isoperatively connected through a cable 72 connected at connector 76 to anablation therapy source 78. Stepping on foot pedal 70 would causetherapy source 78 to immediately cease delivery of therapy.

FIGS. 5 and 6 each are a schematic representation of the distal sectionof an ablation catheter. In FIG. 5, a distal electrode 80 is positioneddistal to standard electrodes 82. Pressure sensors 86 are positioned onthe proximal surface 88 of distal electrode 80, and a single shockabsorber 90 is positioned proximal to distal electrode 80. In FIG. 6, adistal electrode 92 is positioned distal to standard electrodes 94.Pressure sensors 96 are positioned on the proximal surface 98 of distalelectrode 92, and several shock absorbers 100 are positioned proximal todistal electrode 92. It is conceivable that two or more safety featurescould be incorporated into the same catheter such that the operatorwould have the immediate ability to terminate therapy manually as wellas safely control the force and/or pressure delivered to the heart. Inthe event that pressure sensed exceeds a predetermined level or value,an operator would see that that level or value had been exceeded andtrip a kill switch. Alternatively, a controller senses that apredetermined level or value has been exceeded and automaticallygenerates an error message or signal that will cause therapy to cease.

In FIG. 7 a manual remote 110 comprises a kill switch 112. Remote 110 iselectrically connected either wired or wirelessly with a receiver (notshown) that is functionally connected to an ablation therapy deliverysystem. Activation of kill switch 112 results in interruption of therapydelivery by the ablation therapy delivery system. In another embodiment,the kill switch could be connected between the catheter and the therapydelivering generator and/or console and triggered via a remote controldevice.

FIG. 8 is a schematic diagram of a voice activated kill switch for anablation therapy delivery system. A receiver 116 receives a voicecommand from an operator, where the receiver preferably has beenprogrammed to recognize the operator's voice, a certain command orcommands, or a combination thereof. Receiver 116 is functionallyconnected to a kill switch 118, which is interposed between a therapygenerator 120 and an ablation catheter 122. Optionally kill switch 118can be functionally connected directly to either therapy generator 120or ablation catheter 122.

It is conceivable that said configuration for the kill switch could alsobe an on/off switch instead contained directly within the catheterhandle or adapted to a variety of connectors and cables to providemanufacturer/catheter and operator optimized functionality.

FIG. 9 is a view of the end of a cable plug or connector 130 where arigid or semi-rigid cylindrical surface 132 surrounds pins 134. Pins 134are further identified as “1” to “10” and have the functions set forthas follows:

PIN NO. FUNCTION 1 Ablation electrode #1 2 Not used 3 Thermocouple(constantan) 4 Thermocouple (copper) 5 Band electrode #2 6 Bandelectrode #3 7 Band electrode #4 8 Connection check 9 Connection check10 Not used

It is within the scope of the invention that a switching mechanism willnot interrupt all the cable functions but only selected ones, so thatother functions can continue. Here, for example, interrupting thesignals associated with pin 1 would terminate the ablation function.

FIGS. 10A and 10B are top and lateral schematic representations of anablation therapy safety device where a safety member 140 is positionedadjacent female end 142 and male 146 end of a cable 148 and a cable 150,respectively. Safety member 140 comprises sleeve or support members 154that engage respective ends 142, 146. A pressure point or button 156 ispositioned on a bridge member 158 connected to support members 154. Whenbutton 156 is pushed in a downward direction, that is, toward bridgemember 154, a latch 160 on female end 142 is engaged/unlocked andsupport members 154 push against cable ends 142 and 146 to cause them toseparate a predetermined distance, thus interrupting the flow of therapythrough cables 148 and 150. When ends 142 and 146 are pushed backtogether, ablation therapy can flow through cables 148 and 150 once theablation therapy generator or source (not shown) is restarted.

FIG. 11 represents a top view of a cable 170 with a molded cableconnector 172 that is received in and engages a receptacle 176 incatheter handle 178. Cable connector 172 engages or extends slightlyover the proximal end 180 of catheter handle 178, to provide supportfor, for example, a kill switch button 182 that is functionallyconnected to cable connector 172 and/or cable 170.

FIGS. 12A and 12B are schematic representations of a catheter handle 184having a flexible gripper sleeve surrounding the outer surface ofcatheter handle 184. In FIG. 12A, a gripper sleeve 186 having a lengthapproximately one-half of the length of catheter handle 184 has beenslipped over and is in position on catheter handle 184. Sleeve 186 has aon/off or kill switch 188 that is in wired or wireless communicationwith catheter handle 184, cable 189, or some other component that canaffect or interrupt the delivery of ablation therapy. The gripper sleeve190 shown in FIG. 12B has a length substantially the length of catheterhandle 184 and has been slipped over and is in position on catheterhandle 184. There is an opening 196 that fits around deflector 197.Sleeve 190 has a on/off or kill switch 194 that is in wired or wirelesscommunication with catheter handle 184, cable 189, or some othercomponent that can affect or interrupt the delivery of ablation therapy.

Sleeves 186 and 190 can comprise any medically acceptable woven ornon-woven flexible material, such as any flexible and sterilizablepolymeric member that can fit over and on a catheter handle.Advantageously the sleeve material will provide comfort and an enhancedgripping surface, that is, grippability, for the operator's hand orfingers.

FIG. 13 represents a top view of a catheter handle 196 that has areceptacle 198 in its proximal end 200 for receiving a cable connector202 of a cable 204. One or more wires 206 in communication with thewires in cable 204 extend from cable connector 202 or cable 204 to asupport member 208 for supporting a kill switch 210. Support member 208is a flexible substrate that can be positioned on or affixed to catheterhandle 196, such as at proximal end 200. For example, flexible member208 could be glued with a suitable sterile adhesive or tied or strappedto catheter handle 196.

FIG. 14 is one embodiment of an on/off or kill switch that could bepositioned on a catheter handle or elsewhere. Switching mechanism 214comprises a button or switch 216 positioned on a flexible orsemi-flexible substrate 220 that can be tied, strapped, adhered, orotherwise affixed to the distal end of a catheter handle (not shown) orother structure or location, such as a cabinet, table, or even theoperator's person, such as a wrist. Substrate 220 comprises a powersource and electronics to generate a signal, such as an inductive orother signal that will create impedance or otherwise will interruptablation therapy in an ablation catheter system. Alternatively, switchmechanism 214 may transmit a signal to a component that is connected toor in a cable transmitting ablation therapy where the component has areceiver for receiving the signal and a mechanical or electronic switchfor interrupting the ablation therapy.

FIGS. 15A and 15B represent lateral and top views, respectively, of analternative to the embodiment of the invention shown in FIG. 3, where acable segment 230 from an ablation therapy generator (not shown) or agenerator breakout box, such as Boston Scientific's Maestro Box (notshown) engages a proximal portion 232 of a clamshell or injection moldedkill switch casing or member 234 having a button or other activationmeans 236, which can, for example, be a membrane switch. Optionallybutton 236 could comprise an IC connected to a microcontroller.Preferably there will be a splash-proof or water-tight seam aroundbutton 236. A cable segment 238 extends from a distal portion 242 ofkill switch casing 234 to a connector (not shown) to connect to anablation catheter handle (not shown). The length of cable segments 230and 238 in combination with kill switch casing 234, together “thecable,” will vary dependent upon the ablation catheter system used andwhether there is a breakout box or similar connection device. The cableused with an ablation catheter system with a breakout box or a similarconnection device tends to be shorter than a cable used with an ablationcatheter system without a breakout box or similar connection device.

There is internal circuitry (not shown) that electrically orelectronically connects to button 236 and two lights 244, such as LEDs.The colors and state of lights 244 reflect the status of the system. Forexample, when the ablation therapy system is activated and operating,one of lights 244 may glow green. And then, when button 236 is pressedto “kill” the therapy, the green light 244 goes off and the other light244 may glow red. Alternatively, there could be only one light 244 thatchanges color from green to red, or a single light could go on and off,or there could be more lights and different colors.

Kill switch casing 234 comprises a digital timer 248 that is incommunication with a power source, such as a battery 250. Digital timer248 is preset for a predetermined time of operability, such as from 8 to24 hours. A primary purpose of timer 248 and the predetermined time ofoperability is to limit the use of the kill switch and to prohibitre-use.

Battery 250 is mechanically connected to a switching mechanism 254 thatactivates battery 250. Switching mechanism 254 may comprise a pull tab,that is, a piece of plastic tape or film (not shown) that is withdrawnpartly or completely through an opening 258 in kill switch casing 234from a space between a battery terminal and a contact to complete acircuit. Alternatively, movement of a simple slide or switch 256 couldmove battery 250 or a contact so that battery 250 completes a circuit.Preferably whatever mechanical means is employed to activate battery 250is designed so that it cannot disengage battery 250 and thus interrupttimer 248.

Another embodiment of a kill switch according to the invention is shownin FIG. 16, where a wire 260 extends from an opening 262 in a killswitch casing 264. The distal end 266 of wire 260 comprises a killswitch button 270 to be positioned upon and attached to an ablationcatheter handle (not shown) or in a gripper (rubber/foam handle cover;as shown below). Button 270 may have an adhesive lower surface 272. Agripper handle cover could also merely cover the wire which extends fromthe cable-based kill switch to the second kill switch button attached tothe proximal portion of an ablation catheter.

Wire 260 can be integral to kill switch casing 264. Alternatively theproximal end 274 of wire 260 can have a plug 276 that plugs into a jack278 in kill switch casing 264, so that the use of a second button isoptional with this system. Similarly, a handle cover or gripper couldconceal any wires attaching this second button to the cable-basedconnector kill switch.

FIG. 17 is an oblique view of a wire 280 that is secured with clips orfasteners 282 along a cable segment 284 that extends from a kill switch(not shown) to an ablation catheter handle (not shown). Wire 280 mayextend parallel to cable segment 284 or it may spiral around cablesegment 284. Connector 286 is compatible with an opening or connectorreceptacle in a catheter handle (not shown). Button 290, which can be,for example, a membrane switch, has an adhesive or foam tape lower layer292 to attach to a catheter handle (not shown) or other curved surface.Wire 280 could be unclipped from cable segment 284 for certain buttonapplications or locations.

As shown in FIG. 18, a standard catheter ablation handle 300 has beenfitted with a flexible gripper (or handle cover) substrate 302 comprisedof a sterilizable polymeric material. Gripper substrate 302 has aproximally extending wire 304 that is operatively connected to a killswitch casing (not shown), as described above. Wire 304 extends throughsubstrate 302 to a button or other activation means 306 positioneddistal of catheter control knob 310. Gripper substrate 302 performs atleast two functions: it provides a comfortable surface for theoperator's hand and it provides a secure location for button 306.Gripper substrate 302 is sized so that it securely and non-movinglyencompasses catheter handle 300. Optionally there may be fasteners orclosure means that fit gripper substrate 302 to catheter handle 300.

The embodiments shown in FIGS. 16 to 18 are effectively “double” killswitch systems in that the operator has two separate buttons indifferent locations to push to deactivate an ablation catheter system.Only one button needs to be pushed; when one button is pushed, theablation system shuts down and deactivates the other button. The utilityof a catheter-based switching system in which one of the switches ofbuttons resides on the catheter itself (preferably in the thumbposition) satisfies the needs of physicians surveyed who prefer not totake their hand of the catheter handle during the actual delivery ofablative therapy. This embodiment allows for manual termination ofablation therapy without having the operator's hand leave the ablationcatheter.

If the external button, that is, the one not on the kill switch casing,is plugged in, then the operator can use either button to stop theablation therapy. In one aspect of the invention, removing a plug from ajack will stop the generator immediately if the plug is unplugged afterthe ablation therapy starts (in case the operator accidentally unplugsthe external button while moving around). Should that happen, either theplug can be plugged back in and the ablation therapy generatorrestarted, or the generator can just be restarted with the plugunplugged. Optionally the external button will have a light, preferablygreen, in or near the activation area to indicate whether it is pluggedin properly.

EXAMPLE

A standard ablation catheter and a depressible red kill switch wasspliced into the main conductor leading to the distal ablationelectrode. The switch was positioned on the ablation handle forimmediate thumb control, and was reassembled so that all the steerablecomponents functioned according to design specifications. The system wasthen tested in vitro utilizing raw chicken and a standard approved RFablation system. FIGS. 1A and 1B represent a radiofrequency ablationcatheter system employing the kill switch on a standard handle, wherein,a standard ablation catheter was modified to include a red button as akill switch. The system was tested multiple times and consistentlycreated in vitro ablation lesions with precise manual control.Depressing the kill switch immediately terminated therapy deliverythereby preventing inadvertent radiofrequency delivery.

Conclusions: An ergonomic kill switch located in the thumb position on astandard ablation catheter handle provides a novel simple safety featurefor rapid termination of inadvertent ablation therapy. This studydemonstrated the ease of operation of this novel system withparticularly utility during ablation procedures proximal to the normalconduction system (thereby minimizing the risk of inadvertent heartblock).

While certain embodiments of the present invention have been illustratedand described, it will be clear that the present invention is notlimited to these embodiments only. Numerous modifications, changes,variations, substitutions and equivalents will be apparent to thoseskilled in the art, without departing from the spirit and scope of thepresent invention, as described in the following claims.

I claim:
 1. A switching mechanism for an ablation catheter system comprising (i) a longitudinally extending ablation catheter to be operated by one or more principal catheter operators and having a proximal end and a distal end, (ii) a handle attached to the proximal end of the catheter, (iii) a mechanism at the distal end of the catheter for delivering ablation therapy to a desired location, and (iv) an ablation therapy generator or controller in communication with the handle and the distal end of the catheter, which ablation generator or controller must be manually reinitiated to apply or continue ablation therapy, wherein the switching mechanism comprises: a casing having an upper surface and two lateral surfaces; a button or other activation means positioned on the upper surface of the casing; at least one indicator light on the upper surface of the casing to reflect the operational status of the ablation catheter system; an internal timer to limit the duration of operation of the ablation catheter system; and a power source to drive the timer and power the indicator light, wherein pushing the button or other activation means terminates the delivery of ablation therapy, and wherein the internal timer is a digital timer powered by a battery and begins timing when the battery is activated by pulling a tab, pressing a button, or moving a lever, or some other means which removes a connection disrupter located between the battery and at least one of its electrical connections to initiate timing.
 2. The switching mechanism of claim 1, wherein the battery powers both the digital timer and a switching mechanism contained within the ablation catheter, and said timer can be restarted but not reset by a principal catheter operator.
 3. The switching mechanism of claim 1, wherein the digital timer is powered by a power source from the ablation delivery system and begins timing when connected to said power source, wherein the timer can be restarted but not reset by a principal catheter operator.
 4. The switching mechanism of claim 1, wherein the digital timer is activated when the ablation catheter system is removed from sterile packaging by a member connected to the sterile packaging that causes the activation. 